Product category:
Chucks and collets for rotational work
News Release from: Leader Chuck Systems | Subject: Hainbuch collet type chucks
Edited by the Manufacturingtalk Editorial
Team on 30 March 2001
Chucks help rolls form true
The improved concentricity and faster changeover times made possible on turning machines by Hainbuch collet type chucks are playing a key role in holding Formflo's world lead in roll forming.
Combined with big advances in cold-roll forming machines and processes, the improved concentricity and faster changeover times made possible on turning machines by Hainbuch collet type chucks are playing a key role in maintaining Formflo's world lead in the roll forming of ring-shaped components Indeed, such is the Cheltenham-based company's level of success that the workforce has gone up from 47 to 180 over the past 15 years and, today, 85 per cent of output is exported chiefly to Germany and North America
This article was originally published on Manufacturingtalk on 23 Jun 2008 at 8.00am (UK)
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Formflo's main products are synchroniser sleeves and constant velocity joint cages, produced in rolled or finish machined condition at the rate of 100,000/week.
Main production takes place in five cells with raw tube in at one end and finished components out at the other - and very little manning in between.
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The company, which is owned by the powder metallurgy group Stackpole Limited of Toronto, supplies roll-formed parts to the world's major automotive manufacturers and transmission product manufacturers.
During recent years there have been big improvements in the cold-roll forming processes and machines which Formflo developed in the 1970s.
These include greater accuracy of the roll-formed parts - which in turn has enabled Formflo to take full advantage of developments in 360 deg workholding.
In particular, the squareness and concentricity now achieved during rolling - today well within 10 and 20 microns respectively - means that turning machines can benefit from the all-round gripping capability of the Hainbuch collet chucks to bring dramatic advantages to both product quality and production rates.
As engineering manager, Peter Holt, explains: "Earlier chucks had to hold rings that could not be formed precisely round.
But we have now improved our rolling process, and the design of the product itself has influenced how round the part can be.
And as roundness has improved so the Hainbuch chucks have offered advantages that we could not ignore, like all-round holding and fast changeover." Supplied by Leader Chuck Systems, Hainbuch chucks are fitted to 11 of Formflo's 12 CNC turning machines which between them are responsible for machining rings within the company's five production cells.
The newest of these are four high-speed vertical turning machines each having twin inverted workpiece spindles that bring the work down onto an indexable tool turret.
The four-station turret has two identical tool holders at each station and parts are turned two at a time.
Workpieces are transferred horizontally into and out of the machine in pairs on a step-forward/step-back conveyor.
From this they are picked up and gripped by the two Hainbuch collet chucks at the lower end of the workpiece spindle.
Work is located precisely in the chuck, axially against a back-face locator and radially by the chuck's 360 deg grip match-ground collet.
Referring to the chucks, Formflo's continuous improvement facilitator, Martin Elliott says: "The quality is superb.
I am not going to get a better design of chuck than these.
I bought the first set in 1997 and they are still in action today." With the older workholding system, workpieces were held in a three-point location within the chucks.
This was necessary because rings were not rolled to the concentricity being achieved today.
But it was a difficult, skilled and lengthy job to make any changeover of workholding between batches.
It could take six to seven hours.
"When I went onto the Leader Chuck System stand at MACH 96, a competition was running to see how quickly the Hainbuch chucks could be changed," comments Martin Elliot.
"I was very impressed at the speed, and there was no setting needed which meant the job could be deskilled.
It now takes just 15 minutes to make the changeover on the twin-spindle machines." He says it has completely revolutionised the way changeovers are made.
Now, it is simply a matter of undoing a couple of bolts.
And, although a wide range of work is produced on the machines fitted with the Hainbuch chucks, many of the collets and locators are common so just 16 different sizes of collet and 27 different sizes of locator caters for all work.
The big improvement in changeover times has been a notable benefit as batch sizes have come down to meet customers' changing demands.
Batch sizes for synchro rings range from 4,000 for parts that are fully machined, and therefore go into cells with turning machines, and 30,000 for rolled-only parts produced in the rolling-only cell.
Changeover between batches normally takes place every third or fourth shift.
Martin Elliott again: "Part of my job has been to get stock inventory levels down and you can more easily do that if you can reduce changeover times and run smaller batch sizes.
The Hainbuch chucks make it easier to do that, and changeover is hassle-free.
There is only one way of doing the job, and we can put any operator on it." When Formflo began producing cold-rolled parts, having first developed the specialised rolling machines, it concentrated on part forming.
It has since moved into providing the additional machining and heat treatment operations.
Today, a cell that makes finished parts will prepare the blank from tube stock to a precise weight, roll the blank to form the ring, then pass it through a series of turning, milling and broaching operations.
As well as better concentricity (up to 0.004 mm TIR) and faster changeover times, Hainbuch users like Formflo are benefiting from higher clamping forces - up to 50 per cent more with the same drawbar pull - than conventional jaw or collet chucks.
The chucks are available to handle parts up to 1,000 mm diameter and, as Formflo's experience shows, they are capable of securely holding short length workpieces with the clamping head pulling into its match ground taper.
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